Barrel handling device

ABSTRACT

A grab for lifting barrels stored in a well includes a grasp system provided for example with suction caps for slightly raising a barrel and movable arms provided with extendable fingers used for embracing the barrel and forming a solid support therefore. The elements are provided with cameras and optical fibers to illuminate and inspect the barrel before lifting it. The grab is provided with a mechanism for centering it on the barrel. The grab can be used for processing nuclear fuels.

The subject of this invention is a barrel handling device, normally ofcylindrical or very similar shape, to grasp barrels, to lift barrels,and if necessary, to inspect barrels,

Certain dangerous waste substances are poured into metal barrels to bestored for long periods of time. This is namely the case for irradiatedproducts of the nuclear industry. Special techniques have beenengineered to coat and to vitrify the waste before pouring it into thebarrels, which are then held in a storage installation. They maynevertheless be moved at a later date, to be inspected or transported.

Many barrel handling devices have been designed. Said devices includevarious grasping means such as tongs or clamping jaws which are designedto grab one part of the barrel or another, but which generally present,the inconveniences of failing to provide a tight grip, being too big tobe conveniently lowered into storage wells, not being resilient to theoscillating or tilting movements of the barrel once the latter has beenraised and furthermore not offering the possibility to inspect thebarrel before the latter is grasped and/or once it has been grasped.Yet, if a barrel is torn or cracked, it should not be moved so as toavoid further aggravating any leaks of the dangerous contents; and evenif the barrel is intact, the known devices risk being handledinappropriately or dropping, which could result in the possibility ofthe barrel being broken.

The invention relates to a barrel handling device that unlike theaforementioned devices provides a firm grasp of the barrel, with no riskof the latter being released or being allowed to tilt in any way whilstbeing lifted. Moreover, the device can easily be fitted with means toenable thorough inspection of the surface of the barrel.

The document EP 0 633 215 describes a handling device which also offersthe advantage of providing a good grasp of the barrel by means oftilting fingers that come under the lower periphery of the barrel, whichis hence positioned on said fingers when it is lifted, but thepositioning of the device around the barrel is far more problematic thanwith the invention.

In its most general form, the handling device comprises a system forgrasping the upper surface of the barrel, at least one moveable arm thatcan be moved vertically in relation to the grasp system and next to theperipheral surface of the barrel, and a finger fitted under the arm thatcan be moved under the lower surface of the barrel. Hence, the barrelcan first be grasped by its upper surface, slightly raised by the graspsystem, the one or several arm(s) (there are usually several) arelowered next to the barrel, the finger is extended below the barrel andprovides solid support thereof; the arm counteracts the lateral slidingmovement of the barrel; and the grasp system is relieved although itcontinues to contribute to a stable grasp of the barrel.

Insofar as that to guarantee optimum grabbing results, the grab systemcomprises a centring mechanism provided with fingers that can beextended radially, for example towards a flange of the upper surface ofthe barrel. The grasp system is not adhered to the barrel until all ofthe fingers have touched the flange and have centred it; a favourableconsequence is that each arm may be placed at a short distance from thebarrel so as to secure it more firmly and ensure that the fingerpositions itself adequately under the barrel when it moves.

The device can be positioned correctly even if the barrel is difficultto access, at great depths or in a narrow well.

The means of inspecting the barrel may include means located under thearm, as well as means located within the grab system. These means allowto inspect the upper surface of the barrel and to provisionally decidewhether it can be raised, said means also allowing to inspect theperipheral surface and then the lower surface of the barrel when the armis lowered.

The invention will now be described with reference to the figures.

FIG. 1 gives a general view of the device,

FIG. 2 shows some of the grasp means,

FIG. 3 is a general illustration of the grab,

FIG. 4 shows the finger extension system,

FIG. 5 shows the arrangement of this system and

FIG. 6 shows the system used for centering the grab on the barrel. FIG.1 is addressed.

In the embodiment described herein, the barrels are stored in wells 1slightly larger than themselves.

Sliding units 2 normally closed isolate the wells 1 from the outside butare opened when a barrel needs to be stored or extracted. The device ofthe invention, which is hence used, comprises in particular a mechanicalsystem which is movable in well 1 and that can lower or lift the barrel,hereinafter referred to as grab 3, as well as a transfer and protectionhood 4 that absorbs the radiation emanating from the barrel and thatlies on the well 1 opening during the storage or extraction operation.The hood 4 comprises a cavity which is large enough to accommodate thegrab 3 loaded with the barrel. Other usual parts of the handling deviceare not mentioned hereafter. The invention focuses exclusively on grab3.

The barrels 5 are generally cylindrical in shape and comprise an uppersurface 6, a lower surface 7, a peripheral side surface 8; we can alsothereof distinguish an upper ledge 48 jutting upwards around the uppersurface 6 and which corresponds to the cover bezel in the surfaceferrule. The ledge 49 can exist in another form when the cover isscrewed on or welded, and can nevertheless provide the same grabcentering function.

We are now going to refer to FIG. 2. Grab 1 comprises several units, ofwhich the first described is a grasp system 9 of the barrel 5 of whichthe purpose is to slightly raise said barrel before completing thehanding procedure. It comprises a support 10, at least one suction cap11 (a set of three suction caps arranged in a circle are shown here), aswell as a ball and socket 12 linking the suction cap holder 13 to thesupport 10. By this means, the suction caps 11 can be applied to theupper surface 6 of the barrel 5 even if the latter is inclined, withoutthe support 10 having to be tilted erratically. The rest of thedescription 3 is depicted in FIG. 3.

The ball and socket 12 and the support 10 are suspended from a column14, itself suspended from a cable 15 manipulated from the outside bymeans of a strain sensor 16. The column 14 also bears an upper plate 17.

Another element of the grab 3 is a barrel 5 hooking system 18 and whichcomprises at least one vertical arm 19 (a set of three arms 19 arrangedin a circle are shown here, although only one is illustrated) suspendedfrom a movable plate 20. The movable plate 20 slides across the column14 by means of a recirculating ball screw 21 of which the upper andlower ends are retained in the upper plate 17 and the support 10. A gearmotor 22 mounted on the upper plate 17 rotates the recirculating ballscrew 21 by means of a belt drive 23. A graduated rule 24 is alsomounted between the upper plate 17 and the support 10 parallel to therecirculating ball screw 21, and a position sensor 25 mounted on themovable plate 20 allows to monitor the vertical movements of said plate.The description hereafter refers to FIGS. 3, 4 and 5.

The arms 19 embrace the barrel 5, the radius of their circle beingslightly bigger than that of the peripheral surface 8. Their height isalso slightly bigger than that of the peripheral surface 8.

A finger 26 fitted under them moves under the lower surface 7 of thebarrel once the grab 3 has been completely lowered. The fingers 26extend between a folded position in which they tangentially stretch out,in the circle of the arms 19, and an active position in which theyradially stretch out, under the barrel 5. They are mounted under thearms 19 by hinges 27 which allow them to rotate, and their rotationalmovement is controlled by means of a rod 28 which extends vertically upto the arm 19, where it ends in a lever 29 that a cylinder 30 rotates bymeans of a pull rod 31. Said last two elements are mounted on a supportreferred to as pantile 32, itself mounted on a guide carriage 33, whichslides across a guide rail 34 of an appropriate section mounted on themovable plate 20. The pantile 32 and the guide carriage 33 are moved bya cylinder 35. The same device is present for each of the three arms 19,to allow for variation as required of the radius of the circle that theyembrace. The grab 3 can hence be lowered into narrow wells or be adaptedto barrels 5 of various diameters.

Another element of the grab 3 is a centring device 36 illustrated inFIG. 6, mounted on the suction cap holder 13 and which comprises acylinder 37, a crown 38 which rotates on the suction cap holder 13 and aset of three fingers 39 linked by one of the inner ends to the crown 38and, by the middle, to the suction cap holder 13: the toggle link atthese points is nevertheless movable and comprises a pivot 40 attachedto the suction cap holder 13 and which can slide into a slit 41 made inthe length of the finger 39.

Rotation of the crown 38 operated by the cylinder 37 modifies theorientation of the fingers 39 and the radial position of their outerend. Extension of the fingers 39 continues until all of them touch theledge 49 of the barrel 5 and until the grasp system 9 and moreparticularly the barrel 5 hooking system 18 are centred.

Here is how the barrel 5 is grasped when it is in well 1 (the procedurewould be identical in other locations). The grab 3 is lowered into well1 until the grasp system 9 comes up to the upper surface 6. The centringsystem 36 is switched on, then the suction caps 11 are activated. Thegrab 3 is slightly raised to lift barrel 5. The hooking system 18 isthence switched on, the arms 19 are extended then lowered alongside theperipheral surface 8, and finally the fingers 26 are extended and thearms 19 are tightened. The barrel 5 is then firmly grasped and can belifted without risking failure of the suction caps 11. It is to be notedthat the fingers 26 hold the inner surface 7 of the barrel 5 if thelatter is open and ajar.

An important aspect of the device mentioned hereinabove is thepossibility to carry out inspections to decide whether the barrel 5 canbe extracted without risk or damage. We will now go back to referring toFIG. 3. Lighting is provided by a light source 40 mounted on the upperplate 17 and illuminates the surface of the barrel 5 by means of anetwork of optical fibres 44. The images of the upper surface 6 of thebarrel 5 are captured by a camera 42 (also refer to FIG. 2) mounted onthe bottom of column 14 and directed downwards, forming an ring lightsource 43 which provides the necessary illumination of the upper surface6 as the light is formed around said upper surface. The optical fibres44 extend into each of the arms 19 until they come below the latter, andare also connected to endoscopes or fibrescopes 45 mounted onto thepantiles 32. It becomes possible to illuminate and inspect theperipheral surface 8 then the lower surface 7 as the arms are loweredalongside said peripheral surface and then under said lower surface.

Further embodiments of the device are possible. The suction caps 11 canfor example be replaced by other electromagnetic or mechanical graspingmeans. The lighting system can function with micro-lamps or LEDs. Thevision system integrated into the arm 19 can be directly integrated intothe camera of a video-endoscope.

1. A barrel grasping and lifting device, the barrel being substantiallycylindrical and comprising a lower surface, an upper surface and aperipheral surface, the device comprising: a group system for graspingthe upper surface of the barrel, at least one moveable arm and acentering mechanism, the grasp system includes a support, and at leastone suction cup mounted under the support for sucking the upper surface,the centering mechanism being mounted on said support and comprisingfingers that can be extended radially, the movable arm being verticaland vertically slidable with respect to the support alongside theperipheral surface, and comprising a finger at a lower end of the arm,and means for moving said finger under the lower surface.
 2. A barrelgrasping and lifting device according to claim 1, wherein the graspsystem is suspended from a column, the at least one moveable arm issuspended from a plate sliding along the column, and an elevator systemadjusts the height of the plate of the column.
 3. A barrel grasping andlifting device according to claim 2, wherein the plate comprises acarriage configured to slide radially, and from which the at least onemoveable arm is suspended, and a carriage slide control.
 4. A barrelgrasping and lifting device according to claim 3, wherein the carriagecomprises means for rotating the finger of the movable arm, said meansfor rotating comprising a rod located on the arm.
 5. A barrel graspingand lifting device according to claim 1, further comprising a ball andsocket for mounting said suction cap to said support.
 6. A barrelgrasping and lifting device according to claim 1, further comprisingmeans for inspecting the barrel.
 7. A barrel grasping and lifting deviceaccording to claim 6, wherein the means for inspecting the barrelcomprises means located on the at least one moveable arm, and meanslocated within the grasp system.